Animal of which there are many in the pound (5)

I believe the answer is:
ounce
This could be a double definition.
'animal of which there are many' is the first definition.
'ounce' can be an answer for 'animal' (I've seen this before). I am not certain of the remainder of the definition.
'pound' is the second definition.
(thesaurus)
'in the' acts as a link.
Can you help me to learn more?
(Other definitions for ounce that I've seen before include "On cue (anag.)" , "One-sixteenth of pound" , "Carnivore" , "16 for a pound" , "Jaguar" .)
